The Stud Muffin®

The patented Stud Muffin® is a pre-assembled device and process for sealing abandoned concrete core holes with a fire resistant rating.

The Stud Muffin® design incorporates a rubber seal for restricting water, an intumescent for passive firestopping up to 3 hours, and a steel
structure with a top plate for strength. These units meet ANSI/UL1479 and IBC construction requirements for through floor penetration closures.


  • All-in-one firestop system rated up to 3 hours.
  • Drops in place from the top side without disturbing occupants below.
  • The steel top plate is strong for supporting
    occupancy weight.
  • Floor prep is applied over the surface of the
    Stud Muffin® and carpet, tile or wood installed on top.
  • Bottom muffins are available if local authorities
    require a bottom closure.

The Safety Muffin™

OSHA requires unattended cored holes to be covered within 24 hours (OSHA standard 29CFR, 1910.23(a)(8). The Safety Muffin™
is made with a steel neck which drops inside the hole, a sturdy
steel top plate for coverage and a rubber plug underneath for water resistance.


  • Press in place to cover core holes. Remove by lifting
    up with a screwdriver.
  • Rubber plug restricts water flow and helps secure in place.
  • Safety Muffins™ are made of sturdy steel for structural support
    on construction jobsites and can be used over and over again.
  • Fits flush to the floor to reduce trip hazards and comes in a
    powder coated Safety Yellow finish.

US Patent Numbers 7,827,759 B1 and 7,836,659 B1. Made in the USA.